ABSTRACT
This study focused on the characterization of emulsions and microparticles encapsulating Chavir essential oil (EO) by application of modified whey protein concentrate-maltodextrin (WPC-MD). Different physical, chemical, morphological, thermal, and antioxidant properties and release behavior of spray-dried microparticles were assessed. Antioxidant, solubility, emulsifying, and foaming activities of modified WPC were increased compared to those of primary material. The results indicated that the particle size distribution varied depending on the type of carriers used, with the smallest particles formed by hydrolyzed WPC (HWPC). Binary blends of modified WPC-MD led to improved particle sizes. The spray-drying yield ranged from 64.1% to 85.0%, with higher yields observed for blends of MD with sonicated WPC (UWPC). Microparticles prepared from primary WPC showed irregular and wrinkled surfaces with indentations and pores, indicating a less uniform morphology. The UWPC as a wall material led to microparticles with increased small cracks and holes on their surface. However, HWPC negatively affected the integrity of the microparticles, resulting in broken particles with irregular shapes and surface cracks, indicating poor microcapsule formation. Encapsulating EO using WPC-MD increased the thermal stability of EO significantly, enhancing the degradation temperature of EO by 2 to 2.5-fold. The application of primary WPC (alone or in combination with MD) as wall materials produced particles with the lowest antioxidant properties because the EO cannot migrate to the surface of the particles. Enzymatic hydrolysis of WPC negatively impacted microparticle integrity, potentially increasing EO release. These findings underscore the crucial role of wall materials in shaping the physical, morphological, thermal, antioxidant, and release properties of spray-dried microparticles, offering valuable insights for microencapsulation techniques.
ABSTRACT
In the present work, different parameters of ultrasound treatment were studied for physical modification of corn starch. The results revealed that the influence of sonication strongly depends on temperature (25-65 °C) and exposure time (5-15 min), while concentration (10-20% w/w) and ultrasound amplitude (50 and 100%) have little influence on functional and rheological properties. SEM micrographs demonstrated the damage induced by ultrasound on starch granules' surface. The solubility, swelling power, and gel clarity were increased. Ultrasonication decreased the gelatinisation enthalpy and temperature range while the X-ray pattern and crystallinity remained almost unchanged, except for samples treated at onset temperature as measured by DSC. The pseudoplasticity and consistency coefficient decreased; also, apparent viscosity diminished prominently. The pasting behaviour of samples was altered without any clear change in gel strength characterised by loss factor. The results of the present work provide further insight into the mode of action of ultrasound on modifying corn starch granules.
